xf86drm: Bound strstr() to the allocated data

We are reading at most sizeof(data) bytes, but then data may not contain
a terminating '\0', at least in theory, so strstr() may overflow the
stack allocated array.

Make sure that data always contains at least one '\0'.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/xf86drm.c b/xf86drm.c
index 7e28b4f7..5f587d96 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -2863,7 +2863,7 @@ static int drmParsePciBusInfo(int maj, int min, drmPciBusInfoPtr info)
 {
 #ifdef __linux__
     char path[PATH_MAX + 1];
-    char data[128];
+    char data[128 + 1];
     char *str;
     int domain, bus, dev, func;
     int fd, ret;
@@ -2874,6 +2874,7 @@ static int drmParsePciBusInfo(int maj, int min, drmPciBusInfoPtr info)
         return -errno;
 
     ret = read(fd, data, sizeof(data));
+    data[128] = '\0';
     close(fd);
     if (ret < 0)
         return -errno;